1. Field of the Invention
The present invention relates to an operator cab for heavy equipment capable of preventing a sliding door from rocking or rattling due to vibration and so on being transferred to the cab in a state that the sliding door mounted on the cab is fully opened.
More particularly, the present invention relates to an operator cab for heavy equipment capable of preventing a sliding door from rocking or rattling in X, Y, and Z-axis directions due to a shock or vibration applied to the cab when the sliding door is in an open state.
Here, the X-axis direction as described above means a forward/backward direction of the cab (i.e., a direction in which the sliding door is opened/closed), the Y-axis direction means a right/left direction of the cab, and the Z-axis direction means an upward/downward direction of the cab.
2. Description of the Prior Art
Generally, it is frequent that common heavy construction equipment such as an excavator is operated with its door kept open in order to secure the operator's view and to ventilate an operator cab during the operation of the equipment. During a swinging operation of the equipment in a state that a hinge type door of the cab is kept open in a narrow or limited working environment such as a downtown area, unexpected collision or bumping with external obstructive objects such as buildings, trees, and so forth, may occur.
In order to solve this problem, as shown in FIG. 1, an operator cab having a sliding door mounted thereon has been used to reduce the swing radius of the cab. This operator cab has been proposed in such a way that an outer sidewall of the cab that includes the sliding door is in an arc shape, and the position of the sliding door remains within the swing radius of the cab when the door is opened.
As illustrated in FIGS. 1 to 3d, a conventional operator cab 2 having a sliding door 3 slidably installed on an outer sidewall 2a, which is disclosed in U.S. Pat. No. 5,577,795, includes a plurality of rails 4, 5, and 6 respectively provided on upper, lower, and central parts of the outer sidewall 2a; a plurality of rollers 7, 8, and 9, mounted on the door 3, for supporting the door 3 when the door 3 is slid between a closed position, in which a doorway 2b is closed, and a fully-opened position, in which the doorway is open; and a plurality of pairs of strikers, each pair including female strikers 10 and 12 and male strikers 11 and 13, one of the strikers of each pair being mounted on the door 3 and the other being mounted on the outer sidewall 2a such that at least one pair of strikers are engaged with each other when the door 3 is in its closed position and at least one pair of strikers are engaged with each other when the door 3 is in its fully-opened position. At least one of the pairs of strikers is mounted in such a way that the strikers are engaged with each other at a front edge portion of the door 3 when the door is fully opened, and at least the other of the pairs of strikers is mounted in such a way that the strikers are engaged with each other at a rear edge portion of the door 3 when the door is fully closed. 18 denotes a door lock.
In particular, as shown in FIG. 2, the upper roller 7 includes a guide roller 7a that moves along the upper rail 4 when the door 3 is slid, and the lower roller 8 includes a rolling roller 8a which is rotated in an X-axis direction, moving along the lower rail 5, to support the load of the door 3 when the door 3 is slid, and a guide roller 8b which is rotated in a Y-axis direction to prevent the door 3 from being released from the lower rail 5.
As shown in FIG. 3c, the central roller 9 of the door 3 includes a rolling roller 9a which is rotated in an X-axis direction to support the load of the door 3 when the door 3 is slid, and a guide roller 9b which is rotated in a Y-axis direction to prevent the door 3 from being released from the central rail 6 when the sliding door 3 is slid.
In the case where the excavator is driven when the door 3 is fully opened or closed, the door 3 is rocked left and right or rattles upward and downward due to the shock or vibration applied to the cab 2. As a result, an operator cannot concentrate upon his work to lower the operation efficiency and to cause the occurrence of a safety accident.
Taking the above problems into consideration, a plurality of male and female strikers 10, 11, 12, 13, 14, and 15 are provided on the door 3 and the cab 2 and are engaged with each other, as shown in FIGS. 1 and 2, so as to prevent the door 3 from rocking or rattling due to the vibration being transferred to the cab 2 and to detachably support the door 3, when the excavator works in a state that the door 3 is fully opened (see FIG. 3b) or is closed (see FIG. 3a).
As shown in FIG. 1, locking strikers 16 and 17 are installed on the door 3 and the cab 2, respectively, so as to lock the door 3 in its opened or closed position. Specifically, the locking striker 16 is installed in a position adjacent to a doorway 2b, and the locking striker 17 is installed in a position that gets away from the doorway 2b. 
According to the structure of the conventional cab for heavy equipment as described above, the plurality of male and female strikers 10, 11, 12, 13, 14, and 15 (see FIGS. 1 and 2) and the locking strikers 16 and 17 (see FIG. 1) are installed on the cab 2 and the door 3, respectively, so as to keep the door 3 in a fully-opened or closed state with respect to the cab 2. This causes the number of components and their assembling time and process to be increased with the cost raised. Accordingly, the production efficiency and the price competitiveness thereof are lowered.
In addition, since the strikers 10, 11, 12, 13, 14, and 15 and the locking strikers 16 and 17, which are installed on the cab 2 and the door 3, are outwardly exposed from the door 3, the external appearance of the heavy equipment deteriorates.
In the case of fixing the door 3 to the cab 2 in the opened state, as shown in FIG. 3d, the shock or vibration generated in a direction in which the door 3 is opened (i.e., X-axis direction in the drawing) can be absorbed or suppressed by the structure of the male and female strikers 14 and 15.
However, the shock or vibration generated in the upward/downward direction of the door 3 (i.e., Z-axis direction in the drawing) cannot be effectively suppressed. Also, the shock or vibration generated in the right/left direction of the door 3 (i.e., Y-axis direction in the drawing) cannot be effectively suppressed.
In addition, since the male and female strikers 14 and 15 for fixing the door 3 in the opened state are large-sized and are greatly protruded outward, the external appearance of the heavy equipment deteriorates.